1. Field of the Invention
The invention pertains to clamps of the picture frame type utilizing a plurality of frame engaging corner elements forced inwardly by a tension member.
2. Description of the Related Art
When gluing or otherwise assembling frames, such as picture frames, of a closed configuration defined by a plurality of frame sides interconnected at their ends, which are usually mitered, frame clamps are employed consisting of a corner element engaging each corner of the frame and interconnected by a tension member whereby tensioning thereof inwardly forces the corner elements into engagement with the frame sides to hold the frame sides in the desired relationship during gluing. Clamps of this type are also used when gluing boxes, chair legs, and other four sided articles. Such frame clamps have taken a variety of configurations using a plurality of features, as shown in the following patents typically illustrating frame clamp devices.
U.S. Pat. Nos. 4,171,799; 4,527,784 and 4,560,153 show frame clamps utilizing flexible tension members and separate corner elements wherein the tension member is stressed by a threaded shaft arrangement.
U.S. Pat. Nos. 4,047,710 and 5,161,789 disclose frame clamps using a tensioning strap and corner elements wherein the strap may be tensioned by a ratchet or buckle.
U.S. Pat. Nos. 1,053,556 and 3,224,754 disclose frame clamps using corner elements in conjunction with a flexible tension member wherein anti-friction rollers are used in engagement with the tension member to reduce the frictional forces between the tension member and the corner elements.
Frame clamps such as those disclosed in the above mentioned patents, and those presently available, are relatively complicated and expensive, difficult to use, and not readily adaptable for use with a variety of frame sizes, and heretofore, an inexpensive frame clamp easy to use by the unskilled has not been available.